Administrators of Citrix XenApp (formerly known as: Presentation Server) normally use a Load Evaluator with an empty Schedule Rule to take a server offline for maintenance or troubleshooting purposes. An empty Schedule Rule maximizes the server’s load, thus it won’t accept any new ICA sessions while all active sessions are not affected. Compared to CHANGE LOGON /DISABLE the “Offline Load Evaluator” allows disconnected user’s to reconnect to their sessions, and Administrators are still able to establish new RDP sessions.

The PowerShell script in this article uses MFCOM to create the Load Evaluator and can be used in automated Citrix Farm setups.

Creating a new Load Evaluator and attaching a Rule to it is straightforward: